1. AgMIP 6, Seeking Sustainable Solutions 28-30 June, Montpellier, France
Reducing vulnerability to climate change
in semi-arid Zimbabwe: a multi-model approach
for redesigning smallholder farming futures
Sabine Homann-Kee Tui, Katrien Descheemaeker, Patricia Masikati, Givious Sisito, Roberto Valdivia, Olivier Crespo,
Buhle Francis, Lieven Claessens
Nkayi, Zimbabwe
AgMIP 6, Seeking Sustainable Solutions
28-30 June, Montpellier, France

2. Introduction Maize based crop livestock system:
High Vulnerability – High potential benefits
Low crop productivity; e.g. cereal yields < 0.7 t/ha
Low livestock productivity; e.g. mortality rates 15%
High poverty levels; 76% poor
Food self-sufficiency: 3-10 months
Remind us: Predominant farming systems, provider of food and livelihoods in SSA, most common form of land use
Given the high level of vulnerability, if done well – these systems present a real opportunity to lift people out of poverty.
Key Issues
1. On farm multiple segments and linkages - multiple benefits from diversification, integration, intensification
2. Look beyond the farm scale–.
At the context:
a. Off farm to supplement limited on-farm income
b. Functional value chains to increase the returns on investments on these farms
+involve decision makers to improving the conditions for technologies to be attractive.

3. Introduction
Temperature: Strong signal: +2 to +3.3oC
Precipitation: No strong signal: -0.7 mm/day to +0.5 mm/day; drier start of season
 Adverse effects on crops, grazing land, water, livestock
RCP 8.5 mid century temperature scenarios for all GCMs in Nkayi, Zimbabwe
Climate driver!
Zimbabwe is in the hotspots of climate change – category of mostly affected countries by CC (15-50% reduction in agricultural productivity by 2080 due to CC.
Strong agreement on increase in temperature, less on the decrease in rainfall
RCP 8.5 mid century precipitation scenarios for all GCMs in Nkayi, Zimbabwe

4. Temperature, rainfall, CO2
Modeling components
Climate change
Temperature, rainfall, CO2
Variability, extremes
Water resources
Pests
Weeds
Diseases
Crop
Animal
Grazing land
Biomass production (grain + stover)
Crop suitability
Cropping patterns
Feed intake
Animal growth and health
Milk production
Fertility
Biomass production
Species composition
Herbage quality

5. Modeling framework Climate data Crop Model APSIM, DSSAT
Historical ( ): Mid century ( ):
5 GCMs
Projected changes in temperature, precipitation
Modeling framework
Crop Model
APSIM, DSSAT
Crop management: fertilizer, rotation, varieties,…
Effects on on-farm
crop production
Economic model
TOA-MD
Household characteristics
Agricultural production
Prices, costs
Economic effects of climate change and adaptations
on entire farms
1 GCM in this talk
Livestock model
LivSim
On-farm feed production; rangeland biomass
Effects on livestock production (milk, off-take, mortality rates)
All households (n=160)
Economic impacts
Heterogeneous populations
Types of households

6. Stakeholder engagement
Background information
Re-designed systems
Conceptualization of SSP1, RAP4,
package-2
Conceptualization of SSP2, RAP2, package-1
Stakeholder feedback
Stakeholder feedback
Model runs;
Result interpretation
Understand background for informed discussion with stakeholders
Select knowledgeable stakeholders based on previous experiences, representing experts and decision makers from different disciplines. Consultation in small group, rather than large workshop. Used a list of parameters/drivers to start with, participants add parameters they find relevant. Estimate trends, direction and magnitude for each driver; generate plausible story line that incorporating these drivers.
Write up and external revision, e.g. by universities
Revisit same stakeholders about 2 months later, with independent discussion on scenarios under different assumptions
Use selected parameters as RIA future socio-economic trends
The high vulnerability of farming households in rural areas like Nkayi motivated the search for possibly more radical changes (RAP4 associated with more drastic adaptation packages), that would improve the farming context (e.g. agricultural policies, makets, etc.), allowing farmers implement and benefit more from climate change adaptation strategies.
Model runs;
Result interpretation
Expert discussion SSP1, RAP4
Adaptation options
Expert discussion SSP2, RAP2
Adaptation options
Transformational
change
Incremental
change
External revision
External revision

7. RAP-2, incremental change
Indicators
SSP2, RAP-2: Conventional development
Systems change +
Better crop-livestock integration
Cultivated land area -
20%
Intensified production on less land
Legume cultivation
No change
Herd size
15%
Small increase due to improved feed and animal management
Input use
Fertilizer and improved seed for maize
Off-farm income
10%
Limited alternative options, people rely more on agriculture
RAPS example - Different frame conditions: plausible stories for Zimbabwe, SSP2, contrasting assumptions, generated independently, can be compared with global projections. Example results:
Soil degradation to worsen under pessimistic assumptions, soils to improve with optimistic assumptions
Increases of herd size under optimistic assumptions, as CC adaptation and income opportunity
Higher input use if made available and accessible, with effects on agricultural incomes and imports
SSP2, RAP-2 “Conventional Development”:
In Zimbabwe: positive trends in governance, but limited confidence in investments, poor market participation
Adaptation package-1 “Incremental”
Microdosing fertilizer on maize, maize-mucuna rotation, drought-tolerant maize

8. Effects on crop production
Maize yield
Food self sufficiency
Extremely poor
Poor
Non-poor

9. RAP-2, impacts of adaptation package-1
56%
of farm households
could be negatively affected by
climate change.
Impact of CC in the future
94%
of farm households
could benefit from adaptation to
climate change.
Benefits of adaptation to CC
91%
of farm households
in Nkayi will be below poverty line
Poverty Projection for 2050

10. RAP-4, transformative change
Indicators
SSP2, RAP-2: Conventional development
SSP1, RAP-4: Sustainable development
Systems change +
Better crop-livestock integration ++
Further crop-livestock integration; crop diversification, intensification
Cultivated land area -
Intensified production on less land
45%
Expansion of cultivated land; labor saving techn., better market access
Legume cultivation
No change
+ +
300%
Groundnut and legume forages
Herd size
Small increase due to improved feed and animal management
++ 100%
Large increase; more fodder production, market incentives
Input use
Fertilizer and improved seed for maize
30%
Fertilizer and improved seed for all crops
Off-farm income
Limited alternative options, people rely more on agriculture
10%
Growth in other sectors attracts people, income diversification
SSP1, RAP-4 “Sustainable development”
In Zimbabwe: conducive institutional environment for investment in sustainable solutions
Adaptation package-2 “Transformational”
Set more land in use, cropland diversification, market oriented groundnut production
Crop rotation, inorganic fertilizer and manure application, drought tolerant high-yielding varieties, sowing density, fodder production

11. Effects on crop production
Maize yield
Food self sufficiency
Drastic change – double maize production

12. Effects on livestock production
Annual milk production
Offtake
Offset effects of CC on milk and offtake

13. Economic effects Extremely poor Poor Non-poor
Packages decreased poverty for non-poor by 61% and for poor by 56%. They decreased poverty rates by 9%. These more adaptation packages would not help to achieve substantial impact on the extremely poor. In a future with better markets and access to inputs and services there will still be a third of the population below minimum living standards.
Extremely poor
Poor
Non-poor

14. Systems comparison 58% 73% 43% of farm households
could be negatively affected by
climate change.
Impact of CC in the future
73%
of farm households
could benefit from adaptation to
climate change.
Benefits of adaptation to CC
43%
of farm households
in Nkayi will be below poverty line
Poverty Projection for 2050

15. Lessons for impact assessments
Integrated modelling framework
Assess effects on both crops and livestock, whole-farm economics
Verify climate change adaptation in conjunction with trends in the wider context of socio-economic and institutional development
Visualize trends, adoption and impacts comparisons across farming systems
Iterative process of systems redesign with stakeholders
Identify best-fit interventions and pathways, barriers, enabling conditions
Stakeholders take ownership in research design, generate information on tangible opportunities, to inform solutions for ‘real’ impact
We can assess requirements and impacts of more drastic interventions and pathways, beyond immediate challenges and constraints

16. Lessons for semi-arid Zimbabwe
Climate change is not the cause of poverty in farming systems like Nkayi. Already a high proportion of farms was poor and vulnerable.
Currently promoted technologies, incremental adaptation, benefited most, but gains were insufficient to lift people out of food insecurity and poverty.
Drastic farming system re-design can lead to substantial improvement in productivity, food self-sufficiency and income, but needs to be enabled by policy and institutional interventions.
Hence, what to look for are processes that unlash barriers for farming, and use simulation modeling for this purpose.

17. THANK YOU